Research On Shift Performance Of Sequence Transmission Integrated Shift

AMT transmission,also known as mechanical automatic transmission,is widely used on current heavy-duty vehicles due to its simple structure and easy maintenance.The overloading vehicles always under big load and shift very frequently,which lead to a problem of clutch wear,In order to decrease clutch friction process,reduce the transmission shift time and simplify the shift actuator system,Sequential shift actuator was used.Instead of current double H shift gear mechanism.The integrated sequential transmission system can improve the transmission efficiency and performance.Sequence type shift actuators are modified by the common manual shift mechanism,only have two actions:shift up and shift down,which eliminated the time of choosing shift gear as traditional AMT,Only have to drive the shifting drum can choosing shift gear and shift at the same time,which can reduce the shift time.On the basis of this mechanism,Integration type shifting mechanism is designed,which combine the transmission and clutch control,simplify the shift control system further,Plays a positive role to promote the application on heavy truck.Based on virtual prototype technology,this paper studies the shifting performance of the integrated gear shifting mechanism,which has a reference value to the design of the integrated gear shifting mechanism and its application on heavy duty truck.First of all,Introduce the structure of the integrated transmission mechanism composition and working principle,analysis control of engine,transmission and clutch during the process of shifting.Finally,raise a complete integrated shift operating mechanism and design the parts.Then have a force analysis of automotive transmission system,get the key parameters that affecting shift process,and analysis the engage process shifting clutch,Provide a theory basis to the process of virtual prototype for establishing integrated shift system.Then,using the 3D modeling software CATIA,the interface software Sim Designer and the multi-body dynamics simulation software ADAMS.The virtual prototype model of the integrated shift mechanism was established.,dynamic simulation analysis is carried out on the starting and moving process of the integrated gear shifting mechanism under different working conditions.Then analysis the shifting performance through the simulation results and following conclusions was summarized:(1)The integrated shift mechanism can achieve shifting process during different driving condition and the shift time also lower than existing AMT.(2)The peak torgue of full-load starting process is bigger than null load start,but the shift time is shorter.In actual control we can increase clutch engaging time appropriately to reduce the peak torque in order to get better shifting comfort;(3)During the downshift process,a large peak torque is generated during the engagement due to the high speed difference of the clutch from the moving disk,which can be further optimized through the control of the engine.In the end,the paper summarizes the whole thesis and prospects the follow-up research.